The church says its 5,000 so-called Sea Organization members are religious devotees akin to monks who are exempt from wage requirements and overtime. But two lawsuits filed by two former Sea Org members, as they are known, allege the workers are little more than slave laborers, forced to work 100-hour weeks for pennies and threatened with manual labor if they cause trouble.

Marc Headley and his wife, Claire, are seeking back pay and overtime that could add up to $1 million each, according to their attorney, Barry Van Sickle.

Experts say the plaintiffs face an uphill battle; one similar lawsuit in state court has already been dismissed, although the plaintiff plans to appeal.

But the dispute has nonetheless focused unwelcome attention on the Sea Org, which operates as a nerve center for the church's most important business. While Sea Org members hold positions of authority within the international church, from the public relations team to the top leadership, lower-ranking members make up much of the work force.

The members are Scientology's most devoted followers: they sign a billion-year pledge, vow not to have children and live and work communally.

Scientology has been sued by disgruntled members before, but experts believe these suits are the first to use labor law to challenge the premise that the Sea Organization is akin to a fraternal religious order.

A victory for plaintiffs would "certainly go to the heart of Scientology's self-identification as a religion," said J. Gordon Melton, director of the Institute for the Study of American Religion and author of a scholarly book on Scientology.